The biochemical, immunological, and chemotherapeutic studies will be continued to aid in understanding the role of human and nonhuman oncogenic viruses in the cause and prevention of cancer. The in vitro and in vivo studies with PRLV will be continued. The section will continue the coordinating role in the IARC International Reference Center for human tumor associated viral reagents, as well as being an active reference laboratory both for simian viral reagents. The international activities consisting of the training of foreign scientists, the coordination between the NCI viral oncology and the IARC reference center and supplying and testing of reagents for the reference center and the WHO/FAO simian viruses program will be continued.